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Panic dataserver, stopping it manually, and on restart showing issues with memory , meanwhile business people wants updates in every 5 mins…The situation is really worst for a DBA.

This posting is related to shared memory problem, for cleaning the shared memory:

When we shutdown the Sybase dataserver abruptly, by using the kill -9 or kill -12(or due to any reason automatically).

During the restart, sometime it gives the problem unable to create shared memory region, as below:

os_create_region: shmget (0x%x): %s

os_create_region: Shared memory segment %d is in the way

os_create_region: uninitialized shared memory descriptor

os_create_region: shmat (%d): %

Killing Process may left behind the System V semaphore or shared memory left behind instead of being cleaned up automatically. To eliminate unneeded semaphores or shared memory segments, we need to release semaphore or shared memory segment manually.

For the Semaphores:

Run the command ipcs -sa, it will give all semaphores active in the UNIX box, look for the value “0” in the column NSEMS. 0 values indicate that unused semaphore, find all semaphore for the Sybase user and remove them using command ipcrm -s

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Anurag has more than 6+ years of experience in Sybase Database Development .His Area of expertise includes Performance, Query Optimization, Cost Optimization, TSQL Development. He is also involved in Consultancy to Financial Firms for Database Implementation and Maintenance. He has supported many Global Financial firms and recently started a new portal -Mati Rang. AnVa (Founder) has more than 6+ years Exp in Sybase ASE/REP Database Administration. His area of interest is ASE Implemenation and maintenance , Performace Tunning , Sybase HA ,Shared Cluster and Replication. Also exploring the In-Memory Databases (HANA) , Big Data, Hadoop and Java. He is also supporting the Forum Sybase Team and started this sybaseblog.com in late 2009.Andrew is Guest Blogger on sybaseblog.com. Andrew have been working with Sybase for more than a decade: ASE & RS mostly.
He has written lot of tools that help to manage/monitor the system for ASE and Replication and some tools are on the way..
He is also poet and love to be creative all the way.

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